Materials and Corrosion in LNG Industry - Our Experiences

Liquefied Natural Gas (LNG) industry utilizes a variety of materials to serve its needs in diverse service conditions, from cryogenic to moderately high temp applications, to a multiplicity of corrosive environments. The content of the submission is applicable all across the LNG industry. This paper focuses on the applications and materials used by Qatargas for LNG production, at both onshore and offshore facilities. It examines mechanical and metallurgical concerns with emphasis on areas of corrosion and the solutions devised to address these items of interest. The presentation discusses in detail case studies and Qatargas experience in selection of materials, metallurgical problems faced and their failure mechanisms such as graphitization, sigma phase formation etc.; mechanical in nature such as vibration induced fatigue etc.; corrosion in nature such as crevice corrosion, environmental assisted cracking, flow accelerated corrosion, aggressive environmental corrosion etc. and solutions arrived for each of the cases. These case studies will be supported by data, analysis, with photographs and other relevant facts and figures for reference as well as details of solutions and remedial measures implemented for each of the cases. As subject matter of the presentation presents case studies of problems faced and solutions reached, the information will be directly applicable to similar service conditions and will be of direct significance to LNG industry.